Lean, Green Killing Machines

The emerald ash borer beetle cometh. Ash trees beware.

The emerald ash borer is coming our way and there’s nothing we can do to stop it.

While it may be metallic green and smaller than a penny, the flying beetle is a major destroyer of ash trees. “It doesn’t care if the tree is big, small, sick, dying, young—it knows what an ash tree is and will lay its eggs inside,” says Steve Nagy, a local board-certified master arborist and assistant district manager for The Care of Trees. “It truly wreaks havoc.”

This invasive species came to North America from northeast Asia about two decades ago, likely as a stowaway on shipping pallets. During late summer, mature beetles zip around, laying their eggs between layers of ash bark. When the eggs hatch, the larvae eat their way through the tree, creating S-shaped tunnels inside. This cuts the tree off from receiving water and nutrients and effectively suffocates it—at which point the wood becomes a brittle safety hazard. “[The dead tree] is going to crumble apart, fall, and it could hit fences, sheds and cars,” Nagy says.

Fortunately (or perhaps unfortunately) Arlington’s supply of ash trees has dwindled in recent years due to development and lack of new plantings. Still, Nagy says he treated some two to three dozen local ash trees last year for ash borer damage.

For the moment, the emerald ash borer is top bug, but soon we could see a new destructive insect on the block—the spotted lanternfly. This mothlike, sap-sucking creature is already doing damage in Pennsylvania and could hit our area as early as next summer.